Final answer:
Prolonged aPTT is often caused by hemophilia, vitamin K deficiency, or the use of certain anticoagulants. Hemophilia, either A, B, or C, involves deficiencies in specific clotting factors. Treatment includes supplementation of clotting factors or adjusting anticoagulant therapies.
Step-by-step explanation:
The most common causes of prolonged activated Partial Thromboplastin Time (aPTT) can be attributed to deficiencies or dysfunctions in the clotting factors, particularly those linked to conditions like hemophilia. These genetic disorders, namely hemophilia A (factor VIII deficiency) and hemophilia B (factor IX deficiency), are the most prevalent forms accounting for approximately 80% and 20% of cases, respectively. Both forms are X-linked and typically inherited from a carrier mother to male offspring. Hemophilia C, though rarer, involves a deficiency in factor XI and is autosomal. In all types, hemophiliacs can experience prolonged bleeding from even minor injuries. Treatments may include regular infusions of clotting factors and potentially, in the future, genetic therapy.
Moreover, vitamin K deficiency can also cause prolonged aPTT as it is necessary for the production of several clotting factors by the liver. Another contributing factor can be the use of anticoagulants such as heparin, which directly influence the clotting cascade, thereby prolonging aPTT. It's important to determine the underlying cause of an abnormal aPTT to administer appropriate treatment, such as clotting factor supplementation or modification of anticoagulant therapy.